NAG OC Workshop: Boost your performance with Core i3 overclocking


In a perfect world or at least in an ideal world, we would all own high-powered gaming computers with tons of storage, high-end graphics cards, powerful CPUs and more. Sadly, that’s not the reality and the truth is, in these tough economic times, there are fewer people willing to spend on luxuries like gaming PCs than ever before.

We tend to mostly only cover high-end products here at NAG, but that doesn’t mean that the budget-conscious consumer should be ignored. There’s actually a strong possibility going forward that this more price-oriented market will be the future of most hardware purchases within our borders. That said, being price conscious does not mean that you’re unable to have fun with your PC. More importantly, if you’re in the market for an affordable gaming machine and anything in the Core i5 and i7 range is out of the question, then the Core i3 is probably your only option.

Now do be warned that what follows here is not advocacy for the Core i3 family of CPUs at their reference performance above what AMD may offer for instance. It’s purely pointing out that despite the i3 overclocking blockade by Intel, there’s plenty of fun to be had with an investment in low-power CPUs. Granted you may get similar performance out the box by going the AMD route, but that’s effectively a dead-end at present and an ill-advised path to take. The current AMD platforms are old, underperforming, lacking in features and simply out of step with modern-day computing needs in addition to being obsolete by the end of this year. That will change drastically with the introduction of the AM4+ platform in the fourth quarter of this year, but since we can only ever be in the present, Intel’s Core i3 line of CPUs have presented an attractive alternative for those on a shoestring budget.


The sixth-generation Core i3 CPUs: a special feature about a not-so-special CPU

Depending on your buying habits and interests, you may have already looked at the Core i3 line-up of CPUs. If you haven’t, it’s for the most part filled with uninspired CPUs that are of little use in a modern gaming context. They do the trick for simple office work and enjoying media, but for those looking to play the latest games, they’re simply not worth the bother. There are two exceptions, however, and those are the Core i3 6300 and the Core i3 6320. I would’ve included the Core i3 6100, but its 3MB of L3 cache hinders performance without being much cheaper. Ideally you’ll want to focus on the Core i3 6300 as it can be had for under R2,700 from any reputable online retailer.

Armed with this CPU, you’ll want to go with an Intel Z170-based motherboard as well. Logic wrongly dictates that you should instead look at the often feature-rich H170 motherboards at this price point. Usually that would be sensible given that high-end H170 boards tend to have more functionality than the entry-level Z170 alternatives. Unfortunately, H- and B-series boards don’t have an external clock generator, nor do they support different DRAM multipliers and as such are of no use to you within the overclocking context. With that in mind, you should look at some entry level MSI, ASUS, GIGABYTE or ASRock motherboards. You’ll also need to use specific BIOS versions, dated prior to February 2016. This is important, as later BIOS revisions block the functions you’ll need which are central to this entire feature. If any BIOS is listed as “update microcode/CPU microcode” with a release date more recent than the end of January, do not use that BIOS as it will permanently remove the ability to overclock the CPU.

I’d recommend the GIGABYTE Z170 D3H motherboard with the F5b BIOS. It’s a full ATX board with support for M.2 storage, Intel Gigabit Ethernet, two-way graphics, USB Type-C and an audio solution with an op-amp. It’s pretty standard fare for all modern motherboards. It retails for between R2,300 and R2,600, and it’s one of the boards that’s well worth considering for this exercise.

Armed with your Core i3 6300 and any one of the Z170 motherboards (alongside the correct BIOS), you’ll be able to go about overclocking your CPU by a respectable margin, ranging between 300 and 800MHz. You’re also going to free this CPU from its limiting DDR 2,133MHz memory frequency restriction. This is precisely why you need to purchase a Z170-based board as this simply isn’t possible on any other chipset at present.


Since this isn’t a general guide to overclocking, we’ll skip the basics and instead highlight only what you need to get your system up and running at these higher CPU frequencies. We’re going to assume that:

  • You have a reasonably good CPU cooler from any of the reputable heatsink and cooling unit vendors (Cooler Master, Noctua, Corsair, Thermalright, Zalman, etc.). The Core i3 6300 is only a 51W CPU, but with overclocking that can rise significantly to 100W and beyond.
  • You have at least DDR4 2,400MHz memory or higher. 3,000MHz is likely unusable, thus it’s best to stick to 2,400MHz or 2,666MHz.
  • You have a decent 450 watt PSU from either Corsair, Cooler Master, ANTEC or any other quality brand. No UniQue, CFI, Universal or any of those brands.
  • You have the rest of the hardware you need such as your graphics card of choice, etc.


Ready? OK!

  1. With Core i3 overclocking you’re unable to use your CPU multiplier and are forced to use your base clock, therefore you’ll want to ignore the CPU multiplier and focus on the Bclk setting. Don’t worry about increasing the frequency of other components in the system. The Z170 chipset and the CPUs use a separate clock for the Bclk and the PEG (PCI Express) and DMI clock. For the Core i3 6300 use any Bclk frequency between 107 to 121MHz.
  1. Load or enable your DRAM’s XMP profile.
  1. Set your DRAM memory clock via the DRAM divider/multiplier to around 2,400MHz or the closest frequency to that number as possible. If you have 2,666MHz memory, set it to 2,666MHz or as close as possible. Do not exceed this memory frequency!
  1. Set your CPU core voltage (vCore on some boards) to between 1.35v and 1.4v. Do not exceed 1.4v!
  1. Save (F10) and exit. Your system should restart at the new CPU frequency, higher than the spec’d 3,800MHz. If it does not, check that you have set your DRAM to 1.35V and that you’ve disabled any C states. You may disable EIST as well.
  1. Once this is done, check via CPU-Z that you are now operating your CPU at the new frequency (4,100 to 4,600MHz), and that your memory is also set to between 2,350 and 2,700MHz.



As a result of using these unlocked and unsanctioned BIOS versions, you will lose out on several CPU features, in particular the following:

  • You will not be able to monitor your CPU temperatures using any software at all. This is not an issue though as the Core i3 6300 is a 51W CPU and will remain cool enough well beyond any possible overclocking limit you could apply via this method and these voltages.
  • You will lose all AVX functionality when overclocking and this has a massive impact on software that uses AVX instructions, such as Intel XTU. Games do not seem to use this feature at all and performance is not impacted in the least.
  • Your system will not be able to switch to a lower frequency during idle times or low loads (C-state switching), so your CPU will always be operating at whatever frequency you set via the overclock.
  • Your integrated GPU will be disabled and you won’t be able to use it for Quick Sync or any related tasks.
  • Some PCI Express-based storage solutions will not work with memory speeds higher than around 2,700MHz, so if you wish to use higher frequencies stick to more traditional SATA storage.

If you’re happy to live with these conditions then you’ll gain yourself some significant performance, the likes of which is otherwise unattainable with any Core i3 CPU.

Test system:

  • Intel Core i3 6300
  • Skill TridentZ DDR4 2x4GB 2,666MHz
  • EVGA GTX 780 Ti
  • MSI Z170A Gaming M7
  • Windows 10 x64

Performance gains:

Depending of course on the game or program, what you’ll see is that the overclocking results in some substantial performance gains. Within the four game titles tested, performance gains can be anywhere between 4.73% in the Frostbite-powered Dragon Age: Inquisition to as much as 28.5% in Grand Theft Auto V. This will hold true for many games right across the board, even ones not represented within this article. The extra power that can be unlocked from this kind of overclocking is well worth the sacrifices, because it’ll gain you significant performance in games.

Without this much-increased clock frequency, any investment into a more powerful GPU is a wasted effort, because there simply won’t be enough CPU power to keep the GPU fed.

Remember that overclocking isn’t sanctioned at all by Intel, but given that traditionally it’s been unsupported, this is familiar and comfortable territory. Given the minimal to zero risks involved with this level of overclocking, the performance gains outweigh the losses.

With that said, if you’re still saving up for a more powerful system or your budget is strictly around R7,600, you can still add some massive performance to your system. For those who own locked Core i5 systems, the same holds true and you can use this very same methodology to extract additional performance. It’s one of the few times where overclocking is truly accessible to everyone, and as such it should be taken advantage of.

Be cautious, but have fun and keep pushing.

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